June 20, 2016

expert reaction to study looking at LDL cholesterol levels and heart events in people that have heart disease and are taking statins

An observational study published in JAMA Internal Medicine reported that, in patients with pre-existing ischemic heart disease, those with ‘moderate’ levels of LDL (bad) cholesterol had lower risk of adverse cardiac outcomes when using statins compared to those with ‘high’ levels of LDL cholesterol, but no additional benefit was seen for those with levels defined as ‘low’.

“We know already that statins definitely lower the risk of heart disease, and that the higher someone’s risk of heart problems the more cost-effective statins are (i.e. the fewer people we need to treat to prevent one person suffering a heart attack or stroke). We also know that more intensive cholesterol lowering gives an additional reduction in the risk of heart disease compared with lower or less powerful statins. This isn’t too surprising, since many drugs have more benefit when used in higher dosage.

“This observational study didn’t find that patients with lower cholesterol levels (while on statin treatment) had lower rates of heart disease, but this does not mean that the current guidelines to lower cholesterol are wrong. There were different types of patients in the different groups, which may account for the findings even though the study attempted to correct for this mathematically. For example, the patients with lower cholesterol levels had higher rates of diabetes and so would be predicted to have higher rates of heart problems.

“It is important to remember that all the patients in this study were taking statins, and its findings are certainly not a good reason to stop taking them. If I was going to take such a medication I would want to take the type and dose that was shown in proper clinical trials to most reduce heart disease, and I will still recommend the more effective statins in higher doses. I recommend patients keep an open mind when taking statins, but that they monitor for signs of side effects and that they openly discuss the reasons for being on them and the risks of side effects with their GP or cardiologist.”

Prof. Colin Baigent, Professor of Epidemiology & Deputy Director of the Clinical Trial Service Unit (CTSU), University of Oxford, said:

“This type of observational study is completely the wrong method for studying the effects of drug treatments like statins. We should be guided instead by the results of very large randomized trials, which avoid the biases of observational studies, and which have shown quite unequivocally that lowering cholesterol is effective right down to very low levels.

“In patients with heart disease it is clear from the evidence that pushing cholesterol as low as possible with statins saves lives.”

Dr Tim Chico: “I am a committee member and Treasurer of the British Atherosclerosis Society, a charity established in 1999 to promote UK atherosclerosis research.”

Prof. Colin Baigent: “I jointly coordinate, with Professor Rory Collins, the Cholesterol Treatment Trialists’ Collaboration meta-analysis of all large-scale randomized trials of statin-based treatments. CTSU has received funding from the pharmaceutical industry to conduct randomized trials, including trials of statin therapy, but this work is conducted independently of the source of funding and the trials are sponsored by the University of Oxford.”